再结晶石墨的形成机制  

Formation mechanism of re-grown graphite

作　　者：臧传义[1] 马红安[1] 黄国锋[2] 贾晓鹏[1] 

机构地区：[1]河南理工大学材料学院,河南焦作454000 [2]吉林大学超硬材料国家重点实验室,长春130022

出　　处：《吉林大学学报（工学版）》2007年第5期1097-1100,共4页Journal of Jilin University:Engineering and Technology Edition

基　　金：国家自然科学基金资助项目(50172018);河南理工大学博士基金资助项目(648195)

摘　　要：用高温高压温度梯度法作为实验手段来生长优质宝石级金刚石单晶。发现在金刚石合成的稳定区内(人造石墨碳源已完整为金刚石,而且籽晶上有宝石级金刚石单晶的持续生长),结晶性完整的亚稳态再结晶石墨更容易在相对低压高温区出现,其成核驱动力小于金刚石。本文还首次从过剩溶解度角度讨论了再结晶石墨的形成过程。研究表明:在金属触媒溶液中由高温端扩散下来的大量碳源处于过饱和状态时,再结晶石墨是作为一种中间相首先出现,当压力、温度合适时,再结晶石墨会再次成核为金刚石单晶,否则,再结晶石墨就会稳定保留下来。Large synthetic diamond was grown by temperature gradient method （TGM） under HPHT. It was found that, in the diamond-stable region, where the man-made graphite has been completely transformed into diamond and the gem diamonds are continuously growing on the seed crystals, the re-grown graphite is easier to appear at lower pressure and higher temperature. The driving force for the nucleation of re-grown graphite is smaller than that for diamond crystals. The formation mechanism of re-grown graphite is explained from the point of super-concentration of carbon （diamond or graphite） in the metal solvent. It is suggested that the re-grown graphite appears as the transitional phase first. Then if the P-T condition is suitable the re-grown graphite will re-nucleate into diamond crystals. Otherwise, the re-grown graphite will be retained stably.

关 键 词：凝聚态物理学 再结晶石墨 温度梯度法 金刚石 过剩溶解度 

分 类 号：O469[理学—凝聚态物理]